Patent Document 1 describes a wiring board for mounting an X-ray detection element in an X-ray detection device. This wiring board includes a base formed by stacking a plurality of insulating layers, a plurality of connection pads formed in an X-ray detection element mounting region of an upper surface of the base, and a plurality of terminal electrodes formed on an outer surface of the base. Also, this wiring board includes a plurality of internal wirings formed inside the base in order to connect the plurality of connection pads and the plurality of terminal electrodes. The plurality of internal wirings include a plurality of through conductors disposed below the mounting region. The plurality of through conductors are formed inclined in different directions with respect to the stacking direction of the insulating layers over the plurality of insulating layers, and the mounting region is included in a projection region onto the upper surface of the base through all those through conductors. This wiring board shields reflected X-rays by the plurality of through conductors.